Abstract

Background

The first case of human infection with avian influenza A (H7N9) virus was identified
in March, 2013 and the new H7N9 virus infected 134 patients and killed 45 people in
China as of September 30, 2013. Family clusters with confirmed or suspected the new
H7N9 virus infection were previously reported, but the family cluster of H7N9 virus
infection in Shandong Province was first reported.

Case presentation

A 36-year-old man was admitted to Zaozhuang City Hospital with progressive respiratory
distress and suspicion of impending acute respiratory distress syndrome on April 21.
The chest radiography revealed bilateral ground-glass opacities and pulmonary lesions.
The second case, the first case’s 4 year old son, was admitted to the same hospital
on April 28 with fever and multiple patchy shadows in the bilateral lungs. Both of
the two cases were confirmed to infect with H7N9 virus by the results of real-time
reverse transcriptase-polymerase-chain reaction (rRT-PCR), virus isolation and serum
antibody titer. At the same time, one environment samples was detected positive for
H7N9 virus in the living poultry market in Zaozhuang. The homologous analysis of the
full genome sequence indicated that both viruses from the patients were almost genetically
identical. The field epidemiology investigation showed that the two cases had no recognized
exposure to poultry, but had the exposure to the environment. The second case had
substantial unprotected close exposure to his ill father and developed symptoms seven
days after his last contact with his father. After surgery, the index case and his
son were discharged on May 16 and May 6, respectively. 11 close contacts of both patients
were identified and tested negative both the throat swabs and the serum antibody.

Conclusion

The infection of the index case probably resulted from contact with environmentally
contaminated material. For the son, the probable infection source was from the index
case during unprotected exposure, but the possibility from the environment or other
sources could not be completely ruled out.